A person Who uses prescription glasses experiences difficulties in using an optical instrument such as a telescope, binocular, camera, gun scope or microscope, etc. One concern is that the prescription glasses increase the distance between eyepieces in the optical instrument and person's eyes so that the person does not usually have the full scope of the view which is magnified from the optical instrument.
Another problem is that prescription glasses are anisotropic and have a definite optical center. If the person's eyes look through the prescription glasses at an angle, the prescription with respect to the eyes will change accordingly. Therefore, the prescription at that time does not fit person's eyes.
One method to solve this problem is to wear prescription contact lenses. However, it is usually not convenient to wear contact lenses for a long time and unwear them. Further, oculists usually prefer to prescribe lenses less than full correction. Therefore, it is not proper to use a full correction prescription lens as a contact lens for normal use. Neither is it desirable to use a lower correction contact lens with the optical instrument as this will affect its function.
In addition to the above concerns, a cheap, light and simple auxiliary lens attachment for optical instruments is desired.
U.S. Pat. No. 1,508,043 issued to Barrows discloses an auxiliary lens being embodied in a structure of a microscope to correct refractive errors of the person using the microscope.
U.S. Pat. No. 2,381,101 issued to Bausch discloses an adjustable eye cap for optical instruments.
U.S. Pat. No. 2,610,545 issued to Davidson discloses a telescope having an inclined-axis eye piece.
U.S. Pat. No. 3,351,408 issued to Krewalk discloses a sunlight-filtering ocular adaptor for telescopes permitting the direct viewing therewith of intensely luminous objects.
U.S. Pat. No. 3,594,061 issued to Selvage discloses an eye guard displaceably mounted at a non-prescription eyepiece.
U.S. Pat. No. 4,119,984 issued to Zajac discloses an eyepiece for use in conjunction with an optical instrument of a camera.
U.S. Pat. No. 4,264,123 issued to Mabie discloses a gun telescope bellows-type extender which absorbs gun recoil to prevent injuring to the eye.
U.S. Pat. No. 4,416,528 issued to Breslau et al. discloses a camera lens accessory and a mounting ring construction for positioning and locking lens accessories.
U.S. Pat. No. 4,936,667 issued to Rohr et al. discloses a binocular microscope attachment for correction of ametropia.
The present invention provides numerous advantages over the prior art including the provision of a cheap, simple, light auxiliary lens attachment including a prescription lens having full correction prescription thereon.